Method of concentrating nonsulphide minerals by froth flotation



Patented Sept. 17 1935 PATENT OFFICE METHOD OF CONCENTRATING NONSUL- PHIDE LHNERALS BY FROTH FLOTA- TION Floyd Weed, Jefferson City, Tenn., and Edwin E.

Ellis, Short Hills, N. J. j

No Drawing. Application October 12, 1932, Serial No. 637,542

30 Claims. (Cl. 209-166) This invention relates to ore concentration. methods and more particularly to the concentration of non-sulphide ores by froth flotation.

Heretofore in the art froth flotation has been applied to non-sulphide ores but such methods as have heretofore been applied require the inordinate use of frothing agents. froth modifier .reagents and pulp conditioning agentsfor successful practice especially on low grade ores, minerals and the like.

One of the objects of the present invention is to provide a simple expedient and inexpensive method for the concentration of non-sulphide ores by froth flotation.

Another object of the present invention is to provide an improved reagent for use in the concentration by froth flotation of non-sulphide ores, minerals and the like.

Still another object of the present invention is to provide an improved method for introducing within a flotation'pulp those reagents having a selective affinity for the metalliferous values of non-sulphide ores, minerals and the like.

Other objects and advantages will become apparent as the invention is further disclosed.

In the flotation of non-sulphide ores, minerals and the like the general practice of the prior art is to first flnely grind the ore, preferably to about 100 mesh to ensure that all of the gangue and the metalliferous components are mechanically separated or dissociated. The finely ground ore is then classified to reject substantially all material above about 100 mesh and substantially all material generally classified as slimes and, is

1 thereafter'inade into a sludge or flotation pulp with water, the proportion of solids in the pulp being regulated somewhat with respect to the speciflc non-sulphide ores being treated. Thereafter the reagent having the desired selective aflinity for the metalliferous values of the ore is added. and thoroughly incorporated within the sludge. Occasionally this reagent is added to the finely ground ore either during grinding or after classifying and before making up the flotation pulp,

- depending'upon the physical character of the reagent, the ore and the proportion of metalliferous values contained within the ore. To the ore is then added those frothing reagents, froth modi-E fler reagents and pulp conditioning reagents desired and the thus treated pulp is ready for the flotation cell.

In accordance with invention we have discovered that the principal difficulty attending the practice of froth flotation on non-sulphide ores, minerals and the like and divided metal values in the ore.

the objects of the present obtaining theproper dispersion within the flotation pulp of the particular reagent having the desired selective affinity for the metalliferous values of the ore. =6

Heretofore in the art many reagents having a selective aflinity for the metal values in non-sulphide ores, minerals and the like have been proposed. In general it may be stated that those fatty acids of the saturated and unsaturated series have proven the most generally applicable as a selective reagents. In particular, the fatty acids of the unsaturated series have shown the most desirable characteristics for froth flotation purposes and oleic acid specifically has heretofore given the most desirable results, as this acid has shown the widest range of selective afllnity.

As a specific embodiment therefore but not in any sense a limitation we will describe the pres ent invention as I have applied the same to bene- 20, flciating froth flotation utilizing oleic acid as the reagent having the desired selective affinity for the metal values of a non-sulphide ore. If it is desired to utilize any one or more of the other fatty acids of either the saturated or the unsaturated 2.5 series they may b esubsti-tuted in part or in whole for the oleic acid of the specific embodiment.

Briefly stated, the present invention resides in first preparing an emulsion or what may be hereinafter referred to as a colloidal dispersion of the reagent having the desired selective affinity for the metal values of the ore and in thereafter adding this colloidally dispersed reagent .to the flotation pulp preferably during or after the same has been properly prepared and prior tb feeding 85. the pulp to the froth flotation cell. We have found that the colloidally dispersed reagent disseminates readily throughout the flotation pulp on being added thereto and does not require extended periods of time or extended periods of me- 0 chanical admixing to obtain this dissemination as has heretofore been required by prior art practice and thereby, the period for proper conditioning is substantially reduced. Moreover, due to the colloidal character of the reagent the minute globules of the fattyacid are economically available for wetting or for adhering onto the finely Therefore it is not necessary to use an inordinate excess of reagent to'obtain this surface wetting or adhering. And furthermore due to the colloidal size of the particles of the reagent excessive smearing or adherence of the fatty acid to any one metalliferous particle is substantially avoided.

In the preparation of our colloidally dispersed reagent we preferably use as a medium a water soluble or miscible fluid containing a proportion of a water soluble soap compound which is soluble in the speciflc medium employed. To this medium is added the fatty acid and the admixture is agitated violently and aerated for a suflicient time interval to'form what is substantially known as an emulsion. The proportion of soap added may vary widely depending upon the specific fatty acid employed and upon the specific soap compound employed. To this admixture we may add a small proportion of a stabilizing reagent such as mineral and/or vegetable oils. We may also incorporate within the emulsion a proportion of such mineral and/or vegetable oils in such an amount as may subsequently be desirable to facilitate and/or beneflciate the subsequent flotation process.

As a speciflc embodiment of the practice of the present invention we will describe the preparation of colloidally dispersed oleic acid reagents which we have found useful in the froth flotation of various non-sulphide ores such as chromite ores, iron ores-of different types, manganese ores and the like.

In forming an emulsion or colloidal dispersion of oleic acid for use in the froth flotation of nonsulphide ores, minerals and the like we preferably use as a medium water (preferably dis- 4 tilled water) and a water soluble soap compound.

Other water soluble or miscible fluids than water may be used however or water maybe admixed with these fluids. The specific soap compound used may be varied widely depending upon the particular ore to be subjected to froth flotation,

upon the nature of the-associated minerals and upon the type and quantity of associated mineral salts in the water available for flotation. We have found however for general purpose, use and application soap compounds formed by interaction of one or more of the amines with one or more of the saturated or unsaturated fatty acids are the preferable soap compounds to employ. The reason for this preference is based upon the fact that such soap compounds and in particular the soap compounds of the primary and tertiary amines are of lower basicity than alkali and alkali earth metal hydroxides and consequently upon subsequent use in so-called hard waters do not upon ionization in the flotation pulp tend to interact withthe salts of the alkali and alkali earth metals present to thereby form substantially insoluble alkaline earth metal soaps or the more or less undersirable alkali metal soap compounds. Where such alkali and alkali earth metal salts are not present in solution the more strongly basic secondary and quartemary amine soap compounds may be freely used however. Another reason for such preference lies in the fact that the amines are freely soluble in water and the soap compounds thereof are also freely soluble and readily ionized. ll'rom experience we have also found that the so-called triethanolamine" a commercial grade of this amine accompanied with small amounts of other amine compounds is asatisfactory amine for the purposes of the present invention.

This amine will combine with oleic acid in the ratio of 1 part amine (by volume) to 2.7 parts (by volume) of oleic acid to form a soap. This soap compound is completely soluble in about 35 parts (by volume) of water. We have found that when a proportion of this soap compound is added to water and oleic acid alone or admixed with any desired proportion of any one of the so tilled water containing from .5 to

. sion is obtained. 7 The time interval called fatty acids (saturated or unsaturated) is added thereto and the admixture aerated and mechanically agitated for a prolonged interval of time, that the oleic acid may be colloidally dispersed in the emulsion of air, soap and water. This emulsion will be stable for a relatively long period of time, but may be stabilized for prolonged stability by the addition thereto before forming of small quantities of mineral and/or vegetable oils. The amount of mineral and/or 10 vegetable oils may be increased largely above the amount necessary to obtain stabilization of the emulsion, if desired where such mineral and/or vegetable oils are subsequently desired for addi-- tion to the froth flotation pulp to beneflciate the same and/or to facilitate the concentration of the metal values contained therein.

Instead of employing a small proportion of a soap compound comprised of an amine (triethanolamine) with oleic acid, we may utilize a small proportion of a soap compound comprised of an amine (triethanolamine) with any other fatty acid (saturated or unsaturated) or a soap compound of such an amine with a vegetable oil such as linseed oil, cottonseed oil and the like saponifiable vegetable oils.

If desired for the purposes of facilitating and/or beneficiating the subsequent froth flotation process additions of such materials as pine oil, asphalt, kerosene and the like may be added to the oleic acid, water and amine soap admixture and colloidally dispersed therewith.

As a specific embodiment of the practice of the present invention we prefer to form the oleic acid emulsion by adding the oleic acid slowly to a solution comprised of water containing a proportion of an amine (specifically triethanolamlne) and agitating, thus forming the amine soap compound of the oleic acid substantially simultaneously with the forming of the emulsion. This I method has certain advantages over the method of first forming a soap solution and then adding the oleic acid thereto. The principal advantage lies in the simplicity of this method and in the fact that the amount of suds formed during the slow addition of the oleic acid' progressively increases and this facilitates the forming of the emulsion particularly where the temperatures of the solution approximates the melting point of the oleic acid. In general it is preferable to maintain a temperature between 20 to 30 C." during the forming of the emulsion as this facilitates the colloidal dispersion of the oleic acid.

As an example of this specific embodiment we may form an emulsion-or colloidal dispersion of oleic acid in an aqueous solution comprised in part of an amine soap in the following manner:

(1) 97 to 99.5 parts (by weight) of oleic acid may be added slowly to an equal volume of dis- 3 parts (by weight) of triethanolamine (commercial grade). During the addition of the oleic acid the solution is vigorously agitated and aerated until the emulinvolved is as dependent upon the efilciency of the mechanical agitation. The emulsion thus obtained is dilutable with water but is stable for only a few minutes.

(2) A stable emulsion may be obtained by admixing 3 parts oleic acid with 96.5 parts (by weight) of linseed oil and then slowly adding this admixture to about 150 parts (by weight) of distilled water containing about .5 parts (by weight) of triethanolamine. The solution must also be 75 agitated and aerated during the addition of the linseed oil-oleic acid admixture until the desired emulsion or colloidal dispersion has been obtained. '5 (3) A second stable emulsion may be obtained by admixing 8 parts oleic acid (by weight) with 90 parts (by weight) of cottonseed oil and adding this admixture slowly to 100 parts (by I weight) of distilled water containing about 2 10 parts (by weight) of triethanolamine.

(4) A third emulsion more stable than oleic acid emulsion but less stable than the linseed oil and cottonseed oil emulsions above noted may be made by admixing 3 parts (by weight) of oleic acid with 92 parts (by weight) of kerosene and adding this admixture slowly to an agitated and aerated solution of about 50 parts (by weight) of water containing 1 part (by weight) of triethanolamine.

(5) A stable emulsion containing asphalt and oleic acid may be made by admixing 90 parts (by weight) of asphalt and 18 parts (by weight) of oleic acid and adding slowly to an agitated triethanolamine solution containing about 150 parts (by weight) of distilled water and parts (by weight) of the amine.

In the application of these oleic acid emulsions or colloidal dispersions we have found that'the flrst example given is generally applicable in the 'froth flotation of substantially all non-sulphide ores, minerals and the like as a reagent having a selective afllnity for the metal values therein.

In general, however, it is necessary to add to the flotation pulp certain other reagents such as mineral oils and/or vegetable oils to facilitate the segregation of the gangue and the metal values,

and prepare the flotation pulp for conditioning by the addition of alkali and/or acid and/ or suitable ore particle dispersion agents such as sodium silicate in order to obtain the best results. The 1- speciflc additions that must be made depends naturally upon the ore being treated and the character of water available for forming the pulp.

We have found that this problem of froth flotation using oleic acid as the selective reagent may be greatly simplified and facilitated by incorporatingwithin the emulsion those reagents essential to beneflciate the segregation of gangue from v metal values thereby adding these reagents also in a colloidally dispersed condition.

In Example (2) we have described a colloidal dispersion containing linseed oil which we have found exceedingly serviceable for the froth flotation of the so-called Birmingham red iron'ore which contains as major constituents iron oxide, calcite and silica. This emulsion when added to a properly classified and conditioned flotation pulp emciently effects a concentration of the iron oxide and calcite from the silica with a consumption of approximately 3.5 pounds of emulsion per ton of ore, this amount of emulsion containing 1.35 pounds of the reagents used in making the emulsion.

The same type of an emulsion with diiferent proportions of oil and linseed oil hasbeen found to be efficient in the froth flotation of silicious hematite ores. The asphaltum and oleic acid colloidal dispersion of Example (5) has also been found effective for silicious hematite ores with a consumption of about 10 pounds of emulsion per ton of ore or 3.3 pounds of the reagents.

The kerosene-oleic acid emulsion of Example (3) and the oleic acid emulsion of Example (1) have both been found effective in the separation 75 by froth flotation of chromite from associated minerals. The emulsion of Example (1) however is preferred as the consumption of emulsion per ton of ore is relatively low, averaging about .3" pound per ton of ore whereas the kerosene-oleic acid emulsion consumption is approximately 5 twice this amount. The froth in the oleic acid emulsion is the more stable. To obtain best results in the froth flotation of chromite ores the flotation pulp should be neutralized by the addition of alkali and/or acid to a pH concentration 10 approximating 6.0.

The specific proportions of ingredients disclosed in Examples 1 to 5 inclusive may be varied widely without departing essentially from. the: nature and scope thereof, as for example the linseed oil-oleic acid emulsion of (2) may be varied by using 37.5 parts linseed oil and 3 parts oleic acid and adding this to 58 parts water containing 1.5 parts triethanolamine. This emulsion has also been found to be highly serviceable inzo the froth flotation of Birmingham red iron ores with a rate .of consumption approximating 5- pounds per ton of ore being treated.

Having broadly and specifically defined the present invention and having given speciflc examples of the practice and application of the same, it is apparent that many variations and departures maybe made from the specific embodiments disclosed without departing essentially from the nature and scope of the broadest conception of the present invention and such variations and departures are anticipated as may fall within the scope of the following claims:

What we claim is:

1. The method of concentrating oxidized ores, residues and minerals which comprises agitating and aerating a suspension of said ore in water in the presence of a fatty acid colloidally dispersed in an alk'yl-amine soap solution to form froth bearing the oxidized metal particles of said ore, n. and separating said froth.

2. The method of concentrating oxidized ores, residues and minerals which comprises suspending said ore in water to form a pulp of desired density, adding to the pulp a proportion of a fatty acid, colloidally dispersed in an ethanolamine soap solution, and agitating and aerating said pulp to form a froth bearing the oxidized metal values of said ore, and separating the said froth.

3. In the concentration of oxidized residues. 50. ores and minerals, the method which comprises forming the ore into a flotation pulp, incorporating therein a proportion of a colloidal dispersion of oleic acid colloidally dispersed in an alkyl-amine soap solution, agitating andaerating 65. the pulp to form a froth, and separating the. froth.

4. In the concentration of oxidized residues, ores and minerals. the method whichcomprises forming the ore intoa flotation pulp, incorporating therein a proportion of a fatty acid colloidally 00* dispersed in an alkyl-amine soap solution containing a proportion of an oil stabilizing reagent. agitating and aerating the pulp to form a froth, and separating the froth.

'5. In the concentrating of oxidized ores, resio5 dues and minerals, the method which comprises forming the ore into a flotation pulp, incorporating therein a proportion of oleic acid colloidally dispersed in a triethanolamine soap solution containing a proportion of an oil stabilizing reagent, and thereafter subjecting the pulp. to agitation and aeration effective in forming a froth and separating the froth.

-6. In the concentrating of oxidized ores, residues and minerals, the method which comprises 76 a I I V forming the ore into a flotation pulp, incorporating in said pulp a proportion of a colloidal dispersion of oleic acid, said dispersion including water, oleic acid and a proportion of a fatty acidalkyl amine soap compound at least sufllcient in amount to stabilize said dispersion, and thereafter subjecting the pulp to froth flotation.

7. In the concentrating of oxidized ores, residues and minerals, the method which comprises forming the ore into a flotation pulp, incorporating in said pulp a proportion of a colloidal dispersion including oleic acid, water and a proportion of a triethanolamine soap compound in an amount substantially suflicient to stabilize said dispersion; and thereafter subjecting the pulp to froth'flotation.

8. In the concentrating of oxidized ores, residues and minerals, the method which comprises forming the ore into a flotation pulp, incorporating in said pulp a. proportion'of a colloidal dispersion including oleic acid, oil, water and a proportion of an alkyl-amine soap compound in an amount substantially sumcient to stabilize said dispersion, and thereafter subjecting the pulp to forth flotation.

' 9. In the concentration of oxidized ores, residuesjand minerals by froth flotation, the method of incorporating in the flotation pulp the fatty acid reagent having a selective amnity for the oxidized metal particles of the ore, which comprises colloidally dis'persingthe reagent in an aqueous solution of an alkyl-amine soap compound, and then adding, the desired amount of said dispersion to the said-pulp.

10. In the concentration of oxidized ores residues and minerals by froth flotation, the method of incorporatingin the flotation pulp the fatty acid reagent having a selective afllnity for .the oxidized metal particles of the ore and the oil reagent beneflciating the segregation of ,said oxidized metal particles from the gangue particles which comprises colloidally dispersing said reagents in anaqueous solution of an alkyl-amine soap compound, and then adding desired amounts 'of said dispersions to the said pulp.

11. In the concentration of oxidized ores, residuesand minerals by froth flotation, the method of incorporating in the flotation pulp the mixture of fatty' acid and oil reagents having a selective aiiinity for the oxidized metal particles and beneflciating the segregationof said oxidized particles from .the gangue particles of the ore,

which comprises mixing the said reagents in their desired relative proportions, colloidally dispersing the mixture in an aqueous solution of. 'a

triethanolamine soap compound, and then adding desired amounts of said 12. In the concentration of oxidized ores, residues andminerals by froth flotation, the method of incorporating a fatty acid reagent in the flotation pulp which comprises colloidally dispersing the reagent in an aqueous solution of a triethanolamine soap compound, andthen adding the desired amount of said dispersion .to the'said 13. In the concentration of oxidized ores, residues andminerals by froth flotationjthe method of incorporating a fatty acid reagent in the flotation pulp which comprises colloidally dispersing the reagent in water containing a proportion of triethanolamine in an amount substantiallydispersion the said' persed in an aqueous solution amine soap compound.

suflicient to react with said reagent to form enough amine soap compounds to stabilize said dispersion, and then adding the desired amount of said dispersion to the said pulp.

14. A froth flotation reagent comprising oleic 5 acid colloidally dispersed in water containing a sufficient proportion of an alkyl-amine soap comptziglid to render said dispersion substantially 4 s e.

15. A froth flotation reagent comprised of a 10. fatty acid colloidally dispersed in water containing suflicient alkyl-amine soap to render the dispersion substantially stable.

16. A froth flotation reagent comprised of oleic acid colloidally-dispersed in water containing 15 sufllcient triethanolamine to render the dispersion substantially stable.

17. A froth flotation reagent comprised of a mixture of an oil and a fatty acid, said mixture being colloidally dispersed in water contain- 90 ing a proportion of an 'alkyl-amine soap suflicient irtiaginount to render the dispersion substantially s e..

18. A froth flotation reagent comprised of a fatty acid colloidally solution of an alkyl-amine soap compound.

19. A froth, flotation reagent comprised of a fatty acidcolloidally solution of a fatty acid-alkyl-amine soap compound. so

20. A froth flotation reagent comprised of a fatty acid colloidally dispersed in an aqueous solution of an ethanolamine soap compound.

21. A froth flotation fatty acid colloidally dispersed in an aqueous solution of a triethanolamine soap compound.

22. A froth flotation reagent comprised of oleic acid colloidally dispersed in an aqueous solution of an' alkyl-amine soap compound.

23. A n w flotation reagent comprised '01 9. oleic acid colloidally dispersed in an aqueous" solution of a triethanolamine soap, compound.

24. A froth flotation reagent comprised of oleic acid colloidally dispersed in water containing a proportion of triethanolamine.

25. A froth flotation reagent comprised of a mixture of a fatty acid and an oil colloidally dispersed in an aqueous solution of an alkylamine soap compound.

26. A froth flotation reagent comprised of a mixture of a fatty acid and an oil colloidally dis-' persed in an aqueous solution of a triethanolamine soap compound. v 27. A froth flotation reagent comprised of a mixture of a 'fatty acid and an oil colloidally dispersed in water containing a proportion of triethanolamine.

28. A froth flotationreagent comprised of a mixture of oleic-acid and an oil colloidally dispersed in an aqueous solution of an alkyl-amine soap compound. v

29. A froth flotation reagent comprised of a mixture of oleic acid and an oil colloidally dis-' of'a triethanolas,

30. A froth flotation reagent comprised of a 'mixture of oleic acid and an oil colloidally dispersed in water containing a proportion of triethanolamine.

p ed in an 26;

dispersed-in an aqueous reagent comprised of a Y 

